/*
 * Copyright (C) 2015 Jérémie Galarneau <jeremie.galarneau@efficios.com>
 *
 * SPDX-License-Identifier: LGPL-2.1-only
 *
 */

#include "utils.h"

#include <common/compat/errno.hpp>
#include <common/compat/time.hpp>
#include <common/macros.hpp>
#include <common/time.hpp>

#include <fcntl.h>
#include <poll.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

int64_t elapsed_time_ns(struct timespec *t1, struct timespec *t2)
{
	struct timespec delta;

	LTTNG_ASSERT(t1 && t2);
	delta.tv_sec = t2->tv_sec - t1->tv_sec;
	delta.tv_nsec = t2->tv_nsec - t1->tv_nsec;
	return ((int64_t) NSEC_PER_SEC * (int64_t) delta.tv_sec) + (int64_t) delta.tv_nsec;
}

int usleep_safe(useconds_t usec)
{
	int ret = 0;
	struct timespec t1, t2;
	int64_t time_remaining_ns = (int64_t) usec * (int64_t) NSEC_PER_USEC;

	ret = lttng_clock_gettime(CLOCK_MONOTONIC, &t1);
	if (ret) {
		ret = -1;
		perror("clock_gettime");
		goto end;
	}

	while (time_remaining_ns > 0) {
		ret = usleep(time_remaining_ns / (int64_t) NSEC_PER_USEC);
		if (ret && errno != EINTR) {
			perror("usleep");
			goto end;
		}

		ret = lttng_clock_gettime(CLOCK_MONOTONIC, &t2);
		if (ret) {
			perror("clock_gettime");
			goto end;
		}

		time_remaining_ns -= elapsed_time_ns(&t1, &t2);
	}
end:
	return ret;
}

int create_file(const char *path)
{
	int ret;

	if (!path) {
		return -1;
	}

	ret = creat(path, S_IRWXU);
	if (ret < 0) {
		perror("creat");
		return -1;
	}

	ret = close(ret);
	if (ret < 0) {
		perror("close");
		return -1;
	}

	return 0;
}

int wait_on_file(const char *path)
{
	int ret;
	struct stat buf;

	if (!path) {
		return -1;
	}

	for (;;) {
		ret = stat(path, &buf);
		if (ret == -1 && errno == ENOENT) {
			ret = poll(nullptr, 0, 10); /* 10 ms delay */
			/* Should return 0 everytime */
			if (ret) {
				if (ret < 0) {
					perror("perror");
				} else {
					fprintf(stderr, "poll return value is larger than zero\n");
				}
				return -1;
			}
			continue; /* retry */
		}
		if (ret) {
			perror("stat");
			return -1;
		}
		break; /* found */
	}

	return 0;
}
